Despite the common belief that high stress can trigger a stroke, a new study finds no evidence that distressing life events raise the risk of a particularly deadly type of stroke.

The study, published in the journal Stroke, looked at the relationship between stressful life events and the risk of subarachnoid hemorrhage, where a ruptured blood vessel causes bleeding into the space surrounding the brain. It’s estimated that up to half of cases are fatal.

It’s common for people to attribute a sudden medical problem like stroke to stress, noted senior researcher Dr. Craig S. Anderson, of the George Institute of International Health and the University of Sydney in Australia.

In the case of subarachnoid hemorrhage, he told Reuters Health in an email, it is possible for a sudden rise in blood pressure to cause a rupture in an aneurysm - a weakened area in an artery wall. And subarachnoid hemorrhage does sometimes follow a sudden exertion, during exercise or sex, for example, Anderson noted.

However, whether life’s distressing experiences are associated with a higher risk of the strokes has been unclear.

For their study, Anderson and his colleagues interviewed 388 subarachnoid-hemorrhage survivors about distressing life events they had experienced in the one month and one year preceding the stroke.

The survey focused on 12 general types of stressful events - including the death of a family member or friend, job loss or being the victim of a crime.

The survivors’ responses were then compared with those of 473 “control” participants in the same age range who had never suffered a subarachnoid hemorrhage.

Overall, the study found, most forms of stressful life events showed no relationship with the risk of subarachnoid hemorrhage.

When it came to events experienced in the month before the subarachnoid hemorrhage, two types of stressors - financial or legal problems and the catch-all category of “other significant event” - were associated with an increased risk. Ten percent of survivors reported a financial or legal problem over that month, versus 4 percent of the control group.

However, the researchers report, when they accounted for factors like high blood pressure, smoking and drinking, the links between those two stressors and subarachnoid hemorrhage were only “marginally” significant.

In other findings, there was a link between subarachnoid hemorrhage and having been a victim of a physical assault in the past year (reported by 4 percent of survivors and 1 percent of the comparison group). On the other hand, people who had a family member or friend fall ill or suffer an injury in the past year showed a decreased risk of subarachnoid hemorrhage.

It’s likely, according to the researchers, that because the study tested 12 different types of life events, the few that were weakly tied to the risk of subarachnoid hemorrhage were simply chance findings.

The concept of “stress,” Anderson noted, is a difficult thing for researchers to measure. This study took one approach to doing so, which is to look at rates of major events that are often sources of psychological stress. Individual study participants’ actual responses to those events are unknown.

Still, Anderson said that based on the findings, “we can confidently say that ‘stressful life events’ are not an important risk factor for subarachnoid hemorrhage.”

In terms of prevention, he said, people should instead focus on avoiding or treating established risk factors for subarachnoid hemorrhage, which include smoking and high blood pressure.

SOURCE: Stroke, online April 15, 2010.